STO and GA negatively regulate UV-B-induced Arabidopsis root growth inhibition

ABSTRACT

Studies on UV-B-induced plant photomorphogenesis mainly focus on Arabidopsis shoots (hypocotyl, leaf, petiole, and stem) but less on roots. In the present research, the low-level UV-B (0.2 W·m⁻²) induced a decrease in the number of root cells in the meristem zone and an inhibition of the cell length in the maturation zone of roots in Arabidopsis thaliana L.Heynh (Col-0). UV-B-induced root growth inhibition was recovered by the addition of GA3 to culture media. GA3 played an important role in UV-B-induced inhibition of root growth. The cop1-4 mutant with more meristem cell and longer mature cells exhibited longer root length under low-level UV-B. COP1 acted as a positive regulator of root growth under UV-B, through regulation of cell division and elongation. The sto mutant exhibited a shorter root length under UV-B with similar cell length but fewer meristem cells compared with wild type (Col-0). STO only regulated cell division, but cell expansion was not affected. UV-B radiation also inhibited the root growth of uvr8 mutant, and the degree of inhibition was greater than for wild type (Ler). UV-B inhibited the growth of Arabidopsis root, possibly because it changes the GA signal and inhibited cell division and cell elongation, which be related to COP1 and STO genes.

KEYWORDS:

• Arabidopsis thaliana
• UV-B radiation
• photomorphogenesis
• GA3
• STO gene
• COP1 gene

Abbreviation

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Acknowledgments

We would like to thank Professor Paul Giller from the University College of Cork, Ireland, for checking the English language of the manuscript.

Author contributions

Shaoshan Li designed the research; Hongpeng Hu performed the experiment; Guizhen Lyu and Dongbing Li drafted the manuscript; and Guizhen Lyu, Dongbing Li, and Shaoshan Li read and approved the final manuscript.

Conflict of interest

The authors state no conflict of interest.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant no. 31670266]; the Natural Science Foundation of Guangdong Province [grant no. 2017A030313115]; the Innovation Project of the Graduate School of South China Normal University [grant no. 2016lkxm10]; and the Leading Scientists Project of Guangdong Province, the Guangdong Pearl River Scholar Funded Scheme [2012].